1. Field of Invention
This invention relates to a wrench, particularly to a retractable open-end wrench allowing itself to recover to an orientation to facilitate further rotation without repeatedly drawing up and fitting itself onto a bolt or nut.
2. Description of the Related Art
Conventional wrenches for tightening or loosening bolts or nuts include locking and non-locking types in which the non-locking types allow for use with various sizes of bolts or nuts by adjusting an adjustment rack.
Regardless of being a locking type or a non-locking type wrench, a user must remove the jaws of the wrench from the bolt after the bolt or nut is tightened or loosened upon rotating the wrench over a certain angle in a tightening or loosening direction, recovering the wrench to an orientation facilitating further rotation under a state that the jaws disengage from the bolt or nut, and then fitting the jaws onto the bolt or nut to perform a subsequently tightening or loosening operation. Such operations must be repeated until the bolt or nut is completely tightened or loosened.
Removing and repositioning the wrench causes inconvenience for the user and requires additional space to accommodate the operation for removing the wrench from the bolt or nut for recovering the wrench to an orientation facilitating further rotation under a state that the jaws disengage from the bolt or nut.
To resolve such problems, U.S. Pat. No. 4,437,364 discloses a wrench allowing linear movement of a movable jaw of the wrench with respect to the web to increase a gap of the wrench. However, in such a conventional wrench, because the receiving hole facilitating linear movement of the movable jaw is formed on the web, a driller or a lathe must be implemented to drill a hole in the web, followed by a milling machine to mill a slot along a lateral face of the web in communication with the drill hole. The above manufacturing process requires the use of several machining equipment and creates problems in tapping and deburring the hole, particularly for small-size wrenches.